#include <string.h>

#include "strstack.h"

static char * buf = 0;
static size_t buf_size = 0;
static char * top = 0;

void strstack_use_buffer(char * mem, size_t mem_size) {
    buf = mem;
    buf_size = mem_size;
}

void strstack_clear() {
    top = buf;
}

int strstack_push(const char * s) {
    size_t len = strlen(s) + 1;
    if (buf + buf_size - top >= len) {
	strcpy(top, s);
	top += len;
	return 1;
    } else
	return 0;
}

const char * strstack_pop() {
    if (top == buf)
	return 0;

    --top;
    while (top != buf && *(top - 1) != 0)
	--top;
    return top;
}